The playlist window in the nightlies is not currently a drop target -- that is, I cannot drag and drop files onto the playlist window, adding them to the playlist as is the case with the 0.8 builds. I can drag and drop files on to the main window, which adds them to the playlist but also starts playing the file, which is not what I want.
I'm not sure if this is a planned feature that is just not currently implemented in the nightlies, so I apologise if this request is unnecessary.